The Works Of Messrs. Schneider And Co.

212 MESSES. SCHNEIDER AND CO.’S WORKS. fuse, so that all accidentai firing is rendered impossible ; in addition, the working lever is fitted with a second catch that holds the trigger cam fast during the period of opening, releasing' it only when the breech is completely locked. To open the breech, the gunner presses on the working lever handle to disengage the catch, and turns the lever through 90 deg. backward in one action. When a fresh cartridge-case is introduced the extractor is brought back to its normal position, and to close the breech it is sufficient to turn the working lever forward through 90 deg. If the cartridge-case has not been pushed quite home by band it is driven into the correct position by the spherical block, owing to the two inclined planes with wliich the latter is provided for the purpose. Concentric-Threaded Breech-Blocks for Small and Medium-Calibre Guns (Figs. 716 to 722, Plates CXXII. and CXXIIL).—The first breech-block of this type designed and manufacturée! by Messrs. Schneider and Co. was fitted to a 75-millimetre (2,952 in.) quick-firing gun. As will readily be seen, this arrangement is a natural develop- ment of the spherical block just described. The working lever for opening and closing the breech is on the right- hand side of the gun, and is joined to the breech-block Ly a semi-cylindrical arm fonning a trunnion that rests in a bearing of sitnilar section cut in the rear of the gun. The lever is provided with a movable handle, fitted with a projection which, when the breech is closed, engages in a recess cut in the thickness of the metal at the breech end of the gun. An inside spring presses the projection to the bottom of its socket, and fixes the block when the breech is closed. The firing device consista of three parts all enclosed within the breech-block (see Fig. 722). The catch, formed of a working arm and a cam joined together by a round pin, acts on the inovable trigger fitted to the striker and on the smaller arm of the V-shaped firing spring; the working arm is made with an eye to which the firing line is attachée! ; it is placecl on one side of the breech-block, in a groove made in the concentric threads. When the firing line is pulled, the catch of the cam draws the striker to the rear by bearing on the trigger until it escapes the latter. The striker is then under the action of the firing spring, which drives it against the fuse. All danger of prématuré fire is done away with, as the space cut out of the concentric threads is shaped in such a way that the catch cannot move until tlie breech is completely closed and locked. The éjection of empty cartridge-cases is insured by a two-branched extractor, provided in the rear with a horizontal arm on which the whole weight of the block acts when the opening motion is completed. The travel of the breech-block is limited by a regulating screw, which fits in a soeket eut in the thickness of metal of the working lever, and which, when it is at the bottom of its soeket, projects from tlie inner surface of the lever and runs in a circular groove cut in the gun breech. The development given to this groove régulâtes the travel of the breech-block. To take the mechanism apart, it is sufficient to slacken the regulating screw by a few turns, and bring the working lever back far enough to disengage the threads. Concentric Threaded Breech-Block with Repeat and Automatic Firing Action (Figs. 723 to 726, Plate CXXIIL).—The second type of breech-block contains the principal parts already referred to ; the firing device, however, is fitted on the left-hand side of the gun, the working lever, alone, remaining on tlie right-hand side, I and the concentric threads are not cut out for the firing mechanism, which can be made repeating or with auto- matic action, at will. The striker is cylindrical, and end,s in front in a point which strikes against the fuse; in the rear it is divided into two U-shaped branches. In its lower central part, a slot is cut to receive the V-sbaped spring. The right-hand branch of the striker carries a projection on which the heel of the hånd lever acts direct, while the other is fitted with a stop against wliich the cam of the governing apparatus presses. The latter consists of a cylindrical pin of varying diameters, fitted in a soeket of the same sliape cut in the rear of the gun, and surrounded by a spring which acts both by torsion and compression ; this pin ends in a plate of larger diameter, in which is cut the cam for cocking the striker. On the other end is keyed the catch lever fitted with a tooth which, during the working of the firing system, runs in a groove cut in the thickness of the breech end of the gun on the left-hand side. This groove, which extends through an angle of 120 deg., is made at one end with an incline, up which rises the corresponding inclined surface of the tooth when the gun is fired. The working lever is recessed as in the case of the mechanism last described, and contains a hollow rod free to slide, and kept in position by a spiral spring. This rod is fitted on the end opposite to the handle with two heels (or projections), one of which acts on the pro- jection on t,he right-hand branch of the striker, the other constituting a laich bolt which enters a mortice in the gun when the breach is completely elosed. In order to operate the striker, it is sufficient to cause the catch lever to turn through 120 deg. by means of a firing line ; during this action the cam causes the stop on the left-hand branch of the striker to recede progressively, by bending the firing spring until the instant when the tooth on the catch lever, having con- cluded its rising action on the incline, forces the cam to move to the left and release the striker, which is driven against the fuse under the action of its spring. From the arrangement of the various parts, it will readily be seen that this action can be repeated as many times as is necessary (in the event of a hang-fire), without having to interfère in any way with the breech. To cock the gun automatically, it is sufficient to adjust the catch lever nearly to the firing position by means of a screw with which it is fitted for this purpose, the end of the screw being made to run in a groove in the breech of